Manually operable can openers have been known for many years and may be broadly categorised into three types: a first type having a cutter blade which cuts directly into the top wall of a can, known as a vertical-cutting type can opener, a second type having a cutter blade which cuts into the side wall of the can below the rim, and a third type which cuts partially into the rim of a can, with the second and third being known as laterally-cutting type can openers.
A typical can opener comprises first and second elongate operating elements pivotally connected to each other. Each operating element has a handle portion. One operating element has a rotatable traction wheel pivotally opposite its handle, and the other operating element has a cutter blade pivotally opposite its handle. Movement of the handles relative to each other moves the traction wheel and cutter blade between an inoperative position, to receive a rim of a can between the traction wheel and the cutter blade, and an operative position in which the traction wheel and cutter blade engage the rim of the can. During operation of the can opener the two handles must be firmly held together in one hand while an operating handle is turned (to move the can rim between the cutter and traction wheel) with the other hand.
Two problems with the above can opener are that the best position for holding the handles together is often not the most comfortable position for using the opener, and it can be difficult for persons with a weak grip to squeeze the handles together with sufficient force during operation of the can opener to properly engage the can rim between the cutter and traction wheel.